What is the Tellabs RTXM139-001-C44?
The Tellabs RTXM139-001-C44 is a SFP optical transceiver module, listed by the manufacturer as "SFP, SDH/ETHERNET TRANSCEIVER, 1310 NM, 15 KM, LC CONNECTORS, SINGLE MODE FIBER, FOR S-1.1". It is part of Circular Telecom's surplus and refurbished telecom/IT equipment inventory.
